Actually no, and I know this all too well because a friend of mine was 19 and his girlfriend was just 16 when he got caught "smuggling" her over the Canadian border(he was going there for the weekend and brought her without telling her parents). Even though her parents were pissed that they had to find out from the border patrol they still gave my friend the go.

You're saying to yourself "But they weren't caught ******* in the car crossing the border right?" Well, about that. They were pulled to be searched on their way back into the country and some erhrrm damning evidence was found on a camcorder. So no, it's not just so you can get married and bang it is also for parental consent of banging.